A light emitting diode (LED) is a semiconductor device for generating light using light emission through recombination of electrons and holes. Composite semiconductors such as GaN, GaAs, GaP, GaAaP, GaAlAs, SiC, InP, and InGaP are used as a chip material of an LED. The LED has various merits such as high energy efficiency, low operation voltage, a small size, a long lifespan, and the like.